Ghost!

Arthur asked Reece to find Emma and the rest, although he expected him to be unable to. After all, Reece never met them. To his amazement, Reece agreed and left Arthur's pocket and headed somewhere along the forest atop the cliff. Before he left, he told Arthur that he saw them with him in the teleportation hall. 

Arthur kept running atop the cliff and could see two persuing him from behind while three did the same from below. After a few minutes of pursuit, one of the three below was eliminated. 

'Yeah, follow me. Hunt me down in the Forest of Traps.' Arthur laughed to himself as he avoided another rune. An owl flew over his head and glided toward the forest. Arthur had a hunch this was Reece since it had cooed at him as it flew by. 

It seems the elimination of one of them brought sense to their mind, or maybe fear, as they decided to stop their pursuit. Arthur, however, didn't keep running.